nayloe



(NQ Model.) 2 sheets-sheen 1.. 'J. NAYLOR 8u R. THORNTON.

ROCK DRILL.

, No. 289,300, Patented Nov. 27, 1833.

2 Sheets-Sheet 2.

(No Model.)

J. NAYLOR 8v R. THORNTON.

ROCK DRILL.

No. 289,300. Patented' Nov. 27, 1883.

PETERS. Pwlwlitfmgmpher. Wunhiugon. D. C.

. ton-rod, onnwhich are two hollow pistons with UNTTED STATES PATENT Gatien".

.ioHN NAYLoR AND ROBERT THORNTON, or sTAwELL, vIcToRIAI..

ROCK-DRILL.

SPECIFICATION formingpart of Letters Patent No. 289,300, dated November 27, 188?.

Application led December 21, 1881. (No model.) Patented in Victoria October 10,1881. No. 3 .101;'1in:Tasmani`a October 14, 1881, No. 207; in South Australia October 17, 1881, No. 209,- in New South Wales November 29.118811-"n Queensland December E,

1881. and in New Zealand January Q7, 1882, No. 590.

To all whom it may concern:

Be it known that we, J oHN Nevron and .ROBERT THORNTON, both of Stawell, in the British colony of Victoria, engineers, have invented certain new and useful Improvements in Rock-Drills, of which the following is a specication.

O'ur invention relates to the contrivances which we employ for regulating the supply and exhaust of the air or steam which gives the necessary motion to rock-drills.` These contrivances are simple in construction, ef fective in operation, easily removable, (for repair,) and produce a machine which warrants us in calling ours a noiseless machine. They consist of certain peculiarities in the construction and arrangement of an equilibrium reversing-valve iitted, by preference, above the center of thedrillcylinder. This valve is inc'losed in a cylindrical case, and is made in the form of a hollow double-ended pisholes in a groove on their periphery. At the top of the case, and near each end, are small exhaust-holes, and at the bottom are ports at either end, leading to the cylinder of the drill, and at each end two valve-supply passages leading from the cylinder.

The operation is this, that at each stroke of the drill the pistonthereof opens the valvesupply passages, and the air in its cylinder is conducted to the cylinder containing the equilibrium reversing-valve, forcing it to the opposite end, and thereby opening the eX- haust, and also opening the supply at the other end for the return-stroke.

In order, however, that our invention may be clearly understood, we will now refer to the drawings hereto attached, in Vwhich the same letters indicate the same parts wherever they occur.

Figure l represents a longitudinal sectional elevation of a rock-drill constructed according `to our invention; and Fig. 2, a similarl view of that part of the machine which constitutes our invention, thisgure being shown full size, Awhile the others are only shown halt' size. Fig. 3 is a plan of the whole machine;

Fig. 4, a transverse sectional elevation on the line c c in Fig. 1, and Fig. 5 half-sectional elevation on line b bin Fig. 3.

And lwe would here state that we have shown the whole of a rock-drill in order the better to explain how our invention is to be applied,l and not that there is anything vnew or `of our invention in it beyond what is shown in Fig. 2, and not that our invention is not applicable to any other construction of drill, but to show one which we have found workable. f

A is the cylinder of the drill, and B the piston working therein.

C and G are the alternate supplyfand exhaust passages, and D and D (shown in dotted lines) the passages which alternately conduct the compressed air or steam from the cylinder to actuate the reversing-valve.

E is the cylinder or casing of ourvsliding reversing-valve, the hollow pistons of' which are marked F and F and the hollow doubleended piston-rod G .I l

El H are the twolsets of escape-holes inthe casing.

I is the space between Vthe hollow pistons,

and is for conducting the supply to the passages C and U, alternately.

J is the supply-opening from the air-reservoir or steam-boiler.

It will be seen that in the position shown in the drawings the piston B has finished its instroke, and the compressed air or steam which has been giving it this stroke is eX- hausting through C intohollow piston F', and from thence through hollow rod G to the atmosphere. A small portion of such exhaust, having passed through passage D and acted against the face of piston F', has reversed the equilibrium sliding valve, forcing it to the other end of its cylinder or casing E, thereby opening the port to supply-passage C for the return-stroke of the drill, the holes H allowing the escape of the air or steam which has enteredglthe valve-cylinder, leaving only suttlcient to form a cushion on its returnstroke.

Having thus described thenature of our in- Q usage@ venton and the manner of performing same, pistons F F, and with the main piston B and 1o We Would have it understood that our imthe respective cylinders A and E, as herein provements in rook-drills, for which we-are specified.

desirous of securing Letters Patent, are- JNO. NAYLOR.

5 In a rook-drilling machine operating by the ROBT. THORNTON.

pressure of steam or analogous uid, the hol- Vitnesses: low piston-rod Gf, adapted to discharge freely W. H. KEAsT,

at both ends, in combination with. the hollow EDWD. GILBERT. 

